Telephone system



Feb.. 4, 1930. e. GRIMSEN TELEPHONE SYSTEM Filed May 26, 1928 Ill.

HIVENTO r? VI N E R Mw T m T m H H R L rv Y B Patented Feb. 4,- 1930 I 1,745,791

current into a slow rhythm, and the receiver which may vibrate between two equal con- UNITED STATES PATENT OFFICE GERHARD GRIMSEN, OF BERLIN-STEGLITZ, GERMANY, ASSIGNOR TO 0. LORENZ AKTIENGESELLSGHAFT, OF BERLIN-TEMPELHOF, GERMANY TELEPHONE SYSTEM Application filed May 26,1928, Serial No. 280,890, and in Germany May 28, 1927.

This invention relates to anarrangement On the outer limbs (a) and (b) of a threefor signaling in telephone systems. limbed laminated magnet (d) of the relay Telephone-service, specially on long lines, (19) (Fig. 1 two coils (e) and (f) have been is operated with audio-frequency A. C. to fixed. A third coil is fixed on the medium produce the signals between exchange and limb (0), which eventually may allow a D. O. subscriber. This alternating current is superposed magnetization of the core. A transmitted by the amplifiers in the same way frame (it) is fixed in the notches of the poleas any frequency contained in the speechpieces. which frame is carried by a steel-reed waves. In order not to be obliged to alter (i) (Fig. 2), and which is designed to accomthe calling-devices of the exchanges and submodate a number of wire-windings, which scribers, this current at the input and output will be connected in series with the coils (e) of the toll-line is converted into the usual and (f). The steel-reed is clamped into the -cycle calling-current. Now, as the calling copperblock (k), and equipped with a sliding implements of the lines are continuously conweight m, by means of which it is possible 1 nected in parallel, they may easily be actuto adjust this entire system: frame, steel-reed ated by the frequencies contained within the and tuning-weight to an exactly defined speech. This is avoided by chopping or mechanical resonance; besides the frame on modulating the audio-frequency signalling its upper side, carries a contact-spring (a),

must be circuited in away that it responds tacts (0). These are fixed to the pole-piece and transmits the 25-cycle calling current to of the middle limb (a). the subscriber only, when the two selectivity- When transmitting calls in the usual way demands are fulfilled, viz, when a calling-curon toll-cables the electric system consisting rent of exactly defined periodicity (500 of the coils (e) (f) and the frame-windings, cycles) inthe period of a second exactly deby connection in series with a condenser (C), fined frequency (25 cycles) induces the 'rewill be operated with a natural frequency of ceiver-device to actuate. With the known 500 cycles. Thus the relay connected in devices for this-purpose one or several tubes parallel with the toll-line (f) takes it highest are used as amplifiers, rectifiers and several energy with 500 cycles, as its apparent re- 0 mechanically tuned. resonance relays or sistance shows a minimum at this frequency. electrical tuning-means for one of the 'two The alternating c'urrentpassing the frame frequencies or for both of them. creates a declination of the frame which is These devices are very costly and demand uni-directed on either side. As soon as the a continuous attendance of the service. The 500-cycles current changes its sense, all magpresent invention removes these disadvannetic powers reverse their directions, also the tages in a simple and yet safe way as follows. frame-current,resulting in the same mechani- By the interference of the modulated in lowcal declination. frequency-current or chopped high-fre- Now,when at an audio-frequency-call this quency-current with a relay working on the 500 cycle-current is modulated and inter- 4 principle of an A. C. moving-coil-instrument. rupted in the period of 25 cycles, this current A mechanical device is influenced to vibrate passing the relay exercises the equal mechanin the period of the modulating-frequency, ical force on the frame 25 times per second. thus causing the actuation of. a relay which If the entire mechanical vibrating systems isdoes the transmission of the call in the lower tuned on 25 cycles, it will-after a certain frequency. I lapse of time, say f. i. 1 second-reach its 011 the drawing attached the object of this maximum amplitude of oscillation. In this invention has been illustrated by an example, stage the contact-spring clamped on the and frame alternately touches the two flanking Fig. 1 is the top-view of the device. springs, and by actuating another relay Fig. 2 is the front-view of thedevice. (which does not appear on the drawing atoccur, when calling-current of exactly the eriodicity of 500 cycles with a modulatingequency of exactly 25 cycles is in action.

By the delay of the retransmission-call to 1 second) created by the oscillatory start of the tuned reed until contact is reached, the danger of actuation of this device at certain frequencies contained in the language is considerably reduced, as such frequencies usually appear only for moments.

What I claim is:

1. An arrangement for signalling in telephone-systems, comprising a relay operated by a current of a high frequency modulated b a lower frequency, and a mechanical device operated by said relay, to vibrate at a period equal to the modulating; frequency, said mechanical device consisting of a steel reed, a frame and a block.

2. An arrangement for signalling in telephone-systems, comprising a relay operated by a current of a high frequency modulated .by a lower frequency, and a mechanical device operated by said relay, whereby said mechanical device vibrates in period of the modulating frequency, said mechanical device,

consisting of a steel reed, a frame and a block, said steel reed carrying a sliding weight, whereby said mechanical device obtains a certain swinging movement adapted to the fre quencyof the modulated current.

3. An arrangement for signalling in telephone-systems, comprising a relay operated bya current of higher frequency modulated by a current of higher frequency modulatedin by a low frequency, and a mechanical device controlled to vibrate in a period equal to the modulating frequency, said mechanicaldevice consisting of a steel reed, a frame and a block, said steel reed carryin weight, whereby said mechanica device obtains a certain swinging movement adapted Z to the frequency of the modulated current,

anda contact arranged on the framecon trolled by said mechanical device 4'. An arrangement for 'gnalling in telea sliding current relay, a circuit connected to said relay for impressing modulated currents across said relay, a vibrating member controlled by said relay havin a natural period of vibration equal to the requency of. the modulating currents and a pair of contacts controlled by said vibrating member.

6. In a signalling system, an alternating current relay, an electric circuit connected to said relay for'supplying modulated currents thereto, a vibrating member carried by said relay, said vibrating member having a normal and alternate position and beingnormally held in a predetermined normal position and responsive when said relay is energized by said modulated currents for operation to its alternate position at a frequency equal to said modulating frequenc and an electric circuit controlled by-said vi rating member.

7. In a signalling system, a relay having a first winding,*a source of alternating modulated currentconnect'ed to said first winding for energizingsaid winding, a second winding a-source of direct current forenergizing said second winding, a vibrating member having apredetermined and alternate position, said vibrating member being held in a predetermined normal position by said secand energized winding and being operative in response to energization of said first wind ing by said modulated frequency to move to its alternate position at a frequency equal to ,the modulated frequency and a pair of con-' tactscontrolled'by said vibratin member.

8. Means for converting hig frequency, comprising a relay, a winding of said relay, a moving coil armature for said relay, means to supply both said winding and n f ennl'rzlnnenmsnn. J I

phone-systems, comprising. arelay operated a low frequency, and a'mechanical device in e-a. slidin' weight, whereby saidmechanical current, and a 'contact arranged onthe-frame controlled by said'mechanical device. v

5. In a signalling system, an alternating device 0 tains a certain movement adapted to the frequency of themod'ulated? frequency, currents modulated by current variations of lower frequency, into currents of said lower. 

